Assessment
Why it matters
EPSS is 4.0%; technical severity is CVSS 9.2.
NGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_proxy_v2_module and ngx_http_grpc_module modules. This vulnerability exists when the proxy_http_version to 2 or grpc_pass directives are used to proxy HTTP/2 traffic, the ignore_invalid_headers directive is set to off, and the large_client_header_buffers directive size is larger than 2 megabytes. A remote, unauthenticated attacker, along with conditions beyond their control, could send large headers while creating an upstream request. This may cause a heap-based buffer overflow in the NGINX worker process leading to a restart. Additionally, attackers can execute code on systems with Address Space Layout Randomization (ASLR) disabled or when the attacker can bypass ASLR. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.
Who should care
- Teams operating Dos, Nginx Gateway Fabric, Nginx Ingress Controller +8 more
- Vulnerability and exposure management teams
- Security operations teams monitoring exploitation activity
Response plan
What I would do
- Confirm whether Dos, Nginx Gateway Fabric, Nginx Ingress Controller +8 more is present in the environment.
- Identify affected versions and establish whether vulnerable services are exposed or reachable.
- F5 Security advisory K000161584
- Review relevant security telemetry for evidence of attempted or successful exploitation.
- Document the remediation decision and track it to verified completion.
Treatment intelligence
Remediation intelligence
Vendor sources are listed before government and third-party guidance. Confirm product applicability and change prerequisites before deployment.
Technical details
- CVSS vector
- CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
- CWE
- CWE-122
- Affected versions
- F5 Dos (Start Including 4.3.0, End Including 4.7.0 | Version 4.9.0); F5 Nginx Gateway Fabric (Start Including 1.3.0, End Including 1.6.2 | Start Including 2.0.0, End Including 2.6.3); F5 Nginx Ingress Controller (Start Including 3.5.0, End Including 3.7.2 | Start Including 4.0.0, End Including 4.0.1 | Start Including 5.0.0, End Including 5.5.0); F5 Nginx Instance Manager (Start Including 2.17.0, End Including 2.22.0); F5 Nginx Open Source (Start Including 1.0.0, End Including 1.30.2 | Start Including 1.31.0, End Including 1.31.1); F5 Nginx Plus (Start Including 37.0.0.1, End Excluding 37.0.2.1 | Start Including r33, End Excluding r36 | Version r36 | Version r36); F5 Waf (Start Including 4.10.0, End Including 4.16.0 | Start Including 5.2.0, End Including 5.8.0 | Start Including 5.9.0, End Including 5.13.1); Redhat Discovery (Version -)
- Fixed versions
- F5 Nginx Plus (Fixed from 37.0.2.1, r36); Redhat Update Infrastructure (Fixed from 5.2)
- Published
- 17 June 2026
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
Signal timeline
- CVE published
- Latest EPSS score: 4.0%
- Signal calculated at 16
External references
- Red Hat Third-party advisory RHSA-2026:27197
- Red Hat Third-party advisory RHSA-2026:36331
- Red Hat Third-party advisory RHSA-2026:36364
- Red Hat Third-party advisory RHSA-2026:36618
- Red Hat Third-party advisory RHSA-2026:36639
- Red Hat Third-party advisory RHSA-2026:38847
- Red Hat Third-party advisory RHSA-2026:44481
- Red Hat Third-party advisory RHSA-2026:46836
- Red Hat Third-party advisory Show Bug.cgi